Publications by authors named "Benjamin Sigurgeirsson"

Changes in DNA methylation in specific coding or non-coding regions can influence development and potentially divergence in traits within species and groups. While the impact of epigenetic variation on developmental pathways associated with evolutionary divergence is the focus of intense investigation, few studies have looked at recently diverged systems. Phenotypic diversity between closely related populations of Arctic charr (Salvelinus alpinus), which diverged within the last 10,000 years, offers an interesting ecological model to address such effects.

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Objectives: Gemcitabine/carboplatin treatment is known to cause severe adverse drug reactions which can lead to the need for reduction or cessation of chemotherapy. It would be beneficial to identify patients at risk of severe hematological toxicity in advance before treatment start. This study aims to identify genetic markers for gemcitabine/carboplatin-induced leukopenia and neutropenia in non-small cell lung cancer patients.

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Chemotherapy-induced myelosuppression, including thrombocytopenia, is a recurrent problem during cancer treatments that may require dose alterations or cessations that could affect the antitumor effect of the treatment. To identify genetic markers associated with treatment-induced thrombocytopenia, we whole-exome sequenced 215 non-small cell lung cancer patients homogeneously treated with gemcitabine/carboplatin. The decrease in platelets (defined as nadir/baseline) was used to assess treatment-induced thrombocytopenia.

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Endometrial receptivity is crucial for implantation and establishment of a normal pregnancy. The shift from proliferative to receptive endometrium is still far from being understood. In this paper, we comprehensively present the transcriptome of the human endometrium by comparing endometrial biopsies from proliferative phase with consecutive biopsies 7-9 days after ovulation.

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Complete and accurate genome assembly and annotation is a crucial foundation for comparative and functional genomics. Despite this, few complete eukaryotic genomes are available, and genome annotation remains a major challenge. Here, we present a complete genome assembly of the skin commensal yeast Malassezia sympodialis and demonstrate how proteogenomics can substantially improve gene annotation.

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Background: Strand specific RNA sequencing is rapidly replacing conventional cDNA sequencing as an approach for assessing information about the transcriptome. Alongside improved laboratory protocols the development of bioinformatical tools is steadily progressing. In the current procedure the Illumina TruSeq library preparation kit is used, along with additional reagents, to make stranded libraries in an automated fashion which are then sequenced on Illumina HiSeq 2000.

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It has been unclear whether ischemic stroke induces neurogenesis or neuronal DNA rearrangements in the human neocortex. Using immunohistochemistry; transcriptome, genome and ploidy analyses; and determination of nuclear bomb test-derived (14)C concentration in neuronal DNA, we found neither to be the case. A large proportion of cortical neurons displayed DNA fragmentation and DNA repair a short time after stroke, whereas neurons at chronic stages after stroke showed DNA integrity, demonstrating the relevance of an intact genome for survival.

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RNA sequencing has become widely used in gene expression profiling experiments. Prior to any RNA sequencing experiment the quality of the RNA must be measured to assess whether or not it can be used for further downstream analysis. The RNA integrity number (RIN) is a scale used to measure the quality of RNA that runs from 1 (completely degraded) to 10 (intact).

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Zebrafish (Danio rerio) are used extensively in sleep research; both to further understanding of sleep in general and also as a model of human sleep. To date, sleep studies have been performed in larval and adult zebrafish but no efforts have been made to document the ontogeny of zebrafish sleep-wake cycles. Because sleep differs across phylogeny and ontogeny it is important to validate the use of zebrafish in elucidating the neural substrates of sleep.

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We characterize the effects of sleep deprivation on sleep-wake behavior, neurogenesis and stress in adult zebrafish, and describe light-induced changes in gene expression. Sleep deprivation was performed using two stimuli: mild electroshock and light. Comparisons were made between five groups of fish: naïve; electroshock sleep-deprived and yoked-control; fish exposed to constant light (increasing wakefulness); and fish exposed to constant darkness (increasing sleep).

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We describe, for the first time, the effects of the wakefulness-promoting drug modafinil on sleep and wakefulness in larval zebrafish. Modafinil is currently used to treat narcolepsy, hypersomnia, and shift-work disorder by increasing wakefulness. Tolerance and dependence are limited with modafinil use, differentiating it from common stimulants; however, the neural mechanisms of action of modafinil are still unknown.

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